---
title: "Joules to Watt-hours — J to Wh converter"
description: "1 joule = 0.0002778 watt-hours. Convert joules to watt-hours with a full conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/joules-to-watt-hours/
site: "At One Place"
---

# Joules to watt-hours

**1 joule in watt-hours: 1 J = 0.0002778 Wh**

Wh = J × 0.000277777778

To convert joules to watt-hours, multiply by 0.000277777778. The table below gives the values people look up most often, and the converter works for any number.

## Joules to watt-hours table

*Common joule values converted to watt-hours.*

| Joules | Watt-hours |
| --- | --- |
| 1 J | 0.0002778 |
| 2 J | 0.0005556 |
| 3 J | 0.0008333 |
| 4 J | 0.0011111 |
| 5 J | 0.0013889 |
| 10 J | 0.0027778 |
| 15 J | 0.0041667 |
| 20 J | 0.0055556 |
| 25 J | 0.0069444 |
| 30 J | 0.0083333 |
| 40 J | 0.011111 |
| 50 J | 0.013889 |
| 75 J | 0.020833 |
| 100 J | 0.027778 |
| 250 J | 0.069444 |
| 500 J | 0.13889 |
| 1,000 J | 0.27778 |

## How the conversion works

The relationship is Wh = J × 0.000277777778. Both units measure energy, so the conversion is a fixed factor that never changes.

## Common questions

### How many watt-hours are in one joule?

One joule equals 0.0002778 watt-hours. Wh = J × 0.000277777778.

### How do you convert joules to watt-hours?

Use Wh = J × 0.000277777778. So 10 J is 0.0027778 Wh.

### How many joules are in one watt-hour?

One watt-hour equals 3,600 joules, which is the reverse of the conversion above.

## Related pages

- [Watt-hours to Joules](https://atoneplace.net/convert/watt-hours-to-joules/)
- [Joules to Kilojoules](https://atoneplace.net/convert/joules-to-kilojoules/)
- [Joules to Kilocalories](https://atoneplace.net/convert/joules-to-kcal/)
- [Joules to Kilowatt-hours](https://atoneplace.net/convert/joules-to-kwh/)
- [Joules to British thermal units](https://atoneplace.net/convert/joules-to-btu/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)